Gomez didn't show anyone up last night. He's frustrated with his performance since the trade and he felt he once again missed a hittable pitch. His bat flip was him displaying frustration at himself.
Also, why is it not ok for Gomez to display emotion on the field, but it's ok for players in the opposing dugout to shout at an opponent and escalate the situation because they got their panties in a wad?
Athletes are human beings; some are stoic with their emotions; some, like Gomez, wear them on their sleeve and feed off of them, good and bad. Neither group is really wrong for the way they act, in most cases. And last night was not crossing the line.